Processing Framework and Match-up Database MODIS Algorithm Version 3 By Robert H. Evans University of Miami Miami, FL 33149-1098 April 30, 1999 Appendix 1 - ATBD A1.1 TABLE OF CONTENTS PREFACE .................................................................................................... 6 1.0 INTRODUCTION ...................................................................................... 7 1.1 Algorithm and Product Identification........................................................................7 1.2 Algorithm Overview..........................................................................................7 1.3 Document Scope ..............................................................................................7 1.4 Applicable Documents and Publications .....................................................................7 2.0 OVERVIEW AND BACKGROUND INFORMATION ......................................... 7 2.1 Experimental Objective ......................................................................................7 2.2 Historical Perspective ........................................................................................8 3.0 DESCRIPTION OF ALGORITHM................................................................. 8 3.1 Introduction based on AVHRR-Oceans Pathfinder .........................................................8 Matchup Databases ..............................................................................................8 3.1.1 Global matchup databases............................................................................................................9 3.1.1.1 MODIS Matchup Databases ................................................................................................11 3.1.1.2 SST Matchup Database.......................................................................................................11 3.1.1.3 Time Coordinates ..............................................................................................................13 3.1.1.4 Generation of a satellite data extraction list.............................................................................14 3.1.1.5 Extraction and subsetting Level 1a fields ...............................................................................15 3.1.1.6 Matchup of the in situ and satellite quantities..........................................................................17 3.1.1.7 Quality control and cloud flagging........................................................................................18 3.1.1.8 Ocean color matchup database .............................................................................................18 3.1.1.9 Quantities in the oceancolor matchup record...........................................................................19 3.1.1.10 Merging for the Matchup process........................................................................................22 3.1.2 MATHEMATICAL ASPECTS OF THE ALGORITHM .................................................................22 3.1.2.1 Cloud filtering in the AVHRR Matchup database ....................................................................22 3.1.2.3 Transition to MODIS .........................................................................................................27 3.1.3 Variance or uncertainty estimates................................................................................................28 3.1.3.1 Observation frequency for useful In situ - satellite matchups......................................................28 3.1.3.2 IR Matchup database..........................................................................................................29 3.1.3.2.1 Ocean Color Matchup databases ....................................................................................40 3.1.3.3 Error sources ....................................................................................................................42 3.2 Practical Considerations ................................................................................... 44 3.2.1 Overview ...............................................................................................................................44 3.2.2 Programming/Procedural Considerations......................................................................................44 ATBD 2 3.2.2.1 Overview.........................................................................................................................44 3.2.2.2 SST and ocean color processing requirements.........................................................................45 3.2.2.4 Overall ocean processing time for the Level-2 radiances ...........................................................45 3.2.2.5 Data Volume ....................................................................................................................46 3.2.2.5.1 Volume of data to be transferred to Miami.......................................................................48 3.2.2.5.2 Total volume..............................................................................................................48 3.2.2.6 Network Capacity..............................................................................................................48 3.2.3 Calibration Validation...............................................................................................................48 3.2.3.1 Introduction......................................................................................................................48 3.2.3.2 Satellite Field and Analysis Techniques .................................................................................49 3.2.3.3 Temporal comparison of temperature fields ............................................................................52 3.2.3.4 Comparison of reference climalogy fields ..............................................................................53 3.2.4 Quality Control and Diagnostics .................................................................................................56 3.2.4.2 Potential quality effects of stray light ....................................................................................58 3.2.4.3 Quality control of in situ observations ...................................................................................59 3.2.4.4 Ocean Processing Level-2 Pixel Quality control flags...............................................................63 3.2.4.4.1 SST atmospheric correction processing flags....................................................................66 3.2.4.4.2 Additional SST Flags To Be Added................................................................................67 3.2.4.4.3 Ocean color atmospheric correction processing flags .........................................................68 3.2.4.5 Ocean Processing granule/product level Quality control flags.....................................................74 3.2.5 Exception Handling..................................................................................................................75 3.2.6 Data Dependencies...................................................................................................................75 3.2.7 Output Product ........................................................................................................................76 4.0 Constraints, Limitations, Assumptions..................................................................... 76 5.0 REFERENCES ............................................................................................. 76 LIST OF TABLES Table 1. Continuous Pathfinder time coordinate values each month, 1986-1989. .............................................14 Table 2. Quantities included in the distributed Pathfinder matchup databases..................................................16 Table 3. In situ quantities tentatively identified for inclusion in the Ocean color matchup database.....................20 Table 4. Satellite quantities tentatively identified as needed for ocean color algorithm development ...................21 Table 5. Quantities to be extracted at the time of Level1 subsetting to allow subset processing to level 1b and level 2 products. ....................................................................................................................21 Table 6. Validation test. .......................................................................................................................26 Table 7. Buoy retrieval statistics for fixed mooring and NOAA-9 AVHRR....................................................29 Table 8. M-AERI cruise times and locations ...........................................................................................31 Table 9. Summary Statistics for M-AERI Matchups .................................................................................35 Table 10. MODIS response function.......................................................................................................38 Table 11. Percent difference of SeaWiFS – Buoy nLw’s MOBY time series .................................................42 Table 12. Processing times for L2 and L3 Oceans products.........................................................................45 Table 13. Summary of File sizes for SST and ocean color Archived products. ................................................46 Table 14. Table showing MODIS product number, names and ESDT relationships..........................................47